feat(JjLib): JjLib implementation

src/error.rs

@@ -16,6 +16,10 @@ pub enum Error {
     JjOperation { context: String },
     #[error("Repository is locked by another process")]
     RepositoryLocked,
+    #[error("Could not get current directory")]
+    FailedGettingCurrentDir,
+    #[error("Could not load Jujutsu configuration")]
+    FailedReadingConfig,
     // Application errors
     #[error("Operation cancelled by user")]
     Cancelled,
@@ -40,3 +44,15 @@ impl From<CommitMessageError> for Error {
         Self::InvalidCommitMessage(value.to_string())
     }
 }
+
+impl From<std::io::Error> for Error {
+    fn from(_value: std::io::Error) -> Self {
+        Self::FailedGettingCurrentDir
+    }
+}
+
+impl From<jj_lib::config::ConfigGetError> for Error {
+    fn from(_: jj_lib::config::ConfigGetError) -> Self {
+        Self::FailedReadingConfig
+    }
+}